1. Field of the Invention
Aspects of the present invention relate to an organic thin film transistor, a flat panel display apparatus comprising the same, and a method of manufacturing the organic thin film transistor, and more particularly, to an organic thin film transistor that has a significantly reduced contact resistance between source and drain electrodes and an organic semiconductor layer, and can be easily manufactured, a flat panel display apparatus having the same, and a method of manufacturing the organic thin film transistor.
2. Description of the Related Art
Since the development of polyacetylene which is a conjugated organic polymer having semiconductor characteristics, due to its advantages, such as versatility of synthesis, easy formability into a fiber or a film, high flexibility, high conductivity, and low cost, many studies about transistors using the organic material in functional electronic devices and optical devices have been performed.
Conventional silicon thin film transistors include a semiconductor layer having source and drain regions doped with a high concentration of dopant and a channel region formed between the source and drain regions, a gate electrode insulated from the semiconductor layer and located on a region corresponding to the channel region, and source and drain electrodes which respectively contact the source and drain regions.
However, the conventional silicon thin film transistor having the above mentioned structure has drawbacks in that it requires high manufacturing costs, is fragile, and is impossible to use with a plastic substrate since the transistor is produced at a high temperature of 300° C. or more.
Particularly, in flat panel display apparatuses such as a liquid crystal device or an organic light emitting diode, thin film transistors are used as switching devices that control operations of each pixel and driving devices of each of the pixels. To meet the flexibility required together with the thin and large sizes required in the flat panel display apparatuses, the use of a plastic substrate instead of the conventional glass substrate has been attempted. However, when a plastic substrate is used, as described above, a low temperature process must be employed. Therefore, it is difficult to use the conventional silicon thin film transistors.
However, these problems can be solved when an organic film is used as a semiconductor layer of a thin film transistor. Therefore, recently, studies to use the organic thin film transistor as an organic thin film transistor have increased and are now being actively conducted.
However, in the organic thin film transistor, there is a high contact resistance between source and drain electrodes and an organic semiconductor layer.
That is, unlike a silicon semiconductor layer included in a conventional silicon thin film transistor, an organic semiconductor layer included in an organic thin film transistor cannot be doped with a high concentration. Therefore, there is a high contact resistance between source and drain electrodes and an organic semiconductor layer.